This invention relates to building construction and, more particularly, to an improved combined environmental control system and fire protection system for a building in which sprinkler heads are mounted on at least the coolant return lines for an environmental control system.
The use of a heat transfer fluid, usually water, has many advantages in environmental control systems for buildings. For example, such a fluid can be circulated into heat transfer relationship with, and to absorb heat from, indirect heat exchangers through which building air is circulated, lighting fixtures, thermal louvers positioned adjacent windows to intercept radiant solar energy, or interceptors for radiation from other energy sources within a building. It frequently is necessary to remove heat from one portion of a building and, at the same time, to add heat to a different portion of the same building. For example, in cooler climates it frequently is necessary to cool interior spaces within a building and, at the same time, to heat exterior spaces in the building. The heat absorbed by heat transfer fluid circulated through one portion of a building can often be used to add the required heat to a different portion of the same building. Ultimately, the circulated heat transfer fluid is returned to an equipment room, and heat is either transferred to the fluid or from the fluid, as required, to maintain a control temperature. Because of the comparatively high temperature level at which heat from lights, from solar energy and from radiant energy sources within a building can be absorbed and transferred to a heat transfer fluid, a cooling tower can be used to transfer heat from the circulated fluid to atmosphere, under cooling conditions. In this way, the energy requirements for air conditioning of a building can be minimized.
In view of an increasing concern for public safety coupled with increasingly stringent building codes, much attention has been given to the necessity for fire protection in buildings. One approach has been to use materials of construction which are resistant to fire for a limited period of time, presumably for a time sufficiently long to enable occupants of the building to escape to the outside. In my U.S. Pat. No. 3,918,525 which issued on Nov. 11, 1975, it is suggested that sprinkler heads may be connected in a water circulating system which is normally used for transferring heat from energy absorbing units within a building, such as lighting fixtures. The absorbed heat is subsequently removed from the fluid in an indirect or closed circuit evaporative cooler. However, the fluid is not cooled below the dew point, to avoid condensation on the circulating system pipes. The sprinkler heads are attached to separate lines which receive water from the circulating system. When a sprinkler head is open, an alarm is generated in response to a flow of water from the system.